Apparatus and method for cementing well liners

ABSTRACT

Apparatus and method for cementing a liner in a well bore in which the apparatus may comprise: a setting tool having a tubular mandrel connected in a pipe string for extension through the liner; a liner wiper releasably disposed within the liner near one end of the mandrel; a plug member for effecting a movable seal behind cement as it is pumped through the pipe string into the liner; a seal assembly sealingly engaging the exterior of the mandrel and the interior of the liner above the liner wiper; and a latch assembly releasably connecting the seal assembly to the liner so as to permit limited axial movement of the mandrel without disturbing the axial position of the seal assembly. In the method of cementing a liner using the apparatus, the force due to pressure applied to the seal assembly, during pumping of cement, is transferred to the liner without transfer to the mandrel.



1. Apparatus for cementing a liner in a well bore comprising: a. a setting tool having a tubular mandrel connected in a pipe string for extension through said liner; b. seal means releasably attached to said liner and sealingly engaging the exterior of said mandrel and the interior of said liner permitting at least limited axial movement of said mandrel without movement of said seal means; c. latch means included with said seal means engageable with corresponding groove means within said liner to releasably hold said seal means against axial displacement therein; and d. said mandrel comprising a first portion and an axially spaced second portion of less diameter than said first portion, said first portion when in registration with said latch means preventing disengagement of said latch means from said groove means, said second portion when in registration with said latch means allowing disengagement of said latch means from said groove means.
 2. Apparatus as set forth in claim 1 in which said sealing engagement between said seal means and said first mandrel portion is interruptable upon axial displacement of said mandrel to a position in which said seal means surrounds said second mandrel portion.
 3. Apparatus as set forth in claim 1 in which said seal means comprises tubular body means, having apertures in which latch members of said latch means are mounted for radial movement between extended positions, in which said latch members engage said groove means, and retracted positions, in which said latch members are not in engagement with said groove means, said mandrel being movable between a first position engaging and holding said latch members in said extended positions, and a second position permitting said latch members to move to said retracted positions.
 4. Apparatus as set forth in claim 1 in which said mandrel is provided with a plurality of radially projecting lug members for centralizing said mandrel within said liner.
 5. Apparatus as set forth in claim 4 in which said lug members are engageable with said seal means upon predetermined axial displacement of said mandrel to permit removal of said mandrel and seal means from said liner.
 6. Apparatus as set forth in claim 1 in which said seal means comprises a sleeve member carrying a first annular seal for sealing engagement with said liner and a second annular seal for sealing engagement with said mandrel.
 7. Apparatus as set forth in claim 6 in which said latch means comprises a plurality of latch members radially movable between extendEd positions, in which said latch members engage said groove means, and retracted positions, in which said latch members are not in engagement with said groove means.
 8. Apparatus as set forth in claim 7 in which said first annular seal is disposed below said latch members a distance greater than the distance between said groove means and any upwardly facing shoulder in said liner above said groove means capable of engagement by said latch members.
 9. Apparatus as set forth in claim 7 in which said mandrel is initially attached to said liner by connector means operable upon rotation of said mandrel to release said mandrel for said limited axial movement relative to said liner.
 10. Apparatus as set forth in claim 9 in which said connector means comprises threads in said liner engageable with a nut member carried by said mandrel.
 11. Apparatus as set forth in claim 10 in which said first annular seal is disposed below said latch members a distance greater than the distance between said threads and said groove means.
 12. Apparatus for cementing a liner in a well bore comprising: a. a setting tool having a tubular mandrel connected in a pipe string for extension through said liner creating an annular space therebetween; b. connector means carried by said setting tool for releasably connecting said liner thereto; c. wiper means releasably disposed within said liner near one end of said mandrel and having a central opening through which cement may be pumped into said liner through said pipe string and mandrel; d. plug means adapted for sliding and sealing engagement with the interior of said pipe string and mandrel effecting a movable seal behind said cement as it is pumped into said liner, said plug means being engageable with said wiper means and movable therewith, upon release of said wiper means, to effect a movable seal behind said cement as said cement is displaced from said liner into said surrounding well bore; e. seal means disposed in said annular space comprising a sleeve member carrying first and second annular seals for sealingly engaging the interior of said liner and the exterior of said mandrel, respectively; and f. latch means releasably connecting said seal means to said liner permitting limited axial movement of said mandrel without disturbing the axial position of said seal means.
 13. Apparatus for cementing a liner in a well bore as set forth in claim 12 in which said connector means is operable by rotation of said mandrel to release said mandrel for said limited axial movement relative to said liner.
 14. Apparatus as set forth in claim 12 in which said latch means comprises a plurality of latches carried by said seal means for movement from extended positions, engaging corresponding surfaces carried by said liner, to retracted positions not engaging said corresponding liner surfaces, said latches being held in said extended positions by the exterior of said mandrel preventing axial movement of said seal means relative to said liner.
 15. Apparatus as set forth in claim 14 in which said first annular seal is disposed below said latches a distance greater than the distance between said connector means and said corresponding liner surfaces.
 16. Apparatus as set forth in claim 14 in which said mandrel is provided with a reduced diameter portion which upon registration with said latch means by predetermined axial movement of said mandrel permits movement of said latches to said retracted positions to permit removal of said seal means from said liner.
 17. Apparatus as set forth in claim 16 in which the sealing engagement of said seal means with said mandrel is interruptable by said reduced diameter mandrel portion upon less than said predetermined axial movement of said mandrel.
 18. Apparatus as set forth in claim 16 in which said mandrel is provided with stop means engageable with said seal means upon further axial movement of said mandrel to remove said mandrel and seal means from said liner.
 19. Apparatus as set forth in claim 18 in which said stop means comprises a plurality of radially projecting lug members centralizing said mandrel within said liner. 